BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/o Vacuum Brake Booster): C126E15; Reservoir Level Switch Circuit Short to Battery or Open; 2022 - 2023 MY RAV4 RAV4 HV [12/2021

Last Modified: 01-30-2024	6.11:8.1.0	Doc ID: RM10000000214Q7
Model Year Start: 2022	Model: RAV4	Prod Date Range: [12/2021 - 10/2023]
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/o Vacuum Brake Booster): C126E15; Reservoir Level Switch Circuit Short to Battery or Open; 2022 - 2023 MY RAV4 RAV4 HV [12/2021 - 10/2023]

DTC

C126E15

Reservoir Level Switch Circuit Short to Battery or Open

DESCRIPTION

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Note
C126E15	Reservoir Level Switch Circuit Short to Battery or Open	The brake fluid level warning switch (brake booster with master cylinder assembly) circuit is open for 2 seconds or more.	Open in brake fluid level warning switch (brake booster with master cylinder assembly) Open in wire harness Uneven brake disc rotor wear Brake fluid leaks Low brake fluid No. 1 skid control ECU (brake booster with master cylinder assembly)	Comes on	SAE Code: C120F Output ECU: Both skid control ECUs

MONITOR DESCRIPTION

When the voltage at terminal LBL of the No. 1 skid control ECU (brake booster with master cylinder assembly) is a specific value or more (open circuit judgment range) for a certain amount of time, the No. 2 skid control ECU (brake actuator assembly) judges that there is an open in the fluid level warning switch circuit and illuminates the MIL and stores this DTC.

MONITOR STRATEGY

Related DTCs	C120F: Reservoir level switch open circuit
Required Sensors/Components(Main)	Brake fluid level warning switch (brake booster with master cylinder assembly)
Required Sensors/Components(Related)	-
Frequency of Operation	Continuous
Duration	2 seconds
MIL Operation	Immediately
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored

U025E: Lost communication with electronic brake booster control unit (C-Bus)

TYPICAL MALFUNCTION THRESHOLDS

Brake fluid level warning switch (brake booster with master cylinder assembly) voltage

+BI1 voltage x 0.7 V or more

COMPONENT OPERATING RANGE

Brake fluid level warning switch (brake booster with master cylinder assembly) voltage

Less than +BI1 voltage x 0.7 V

CONFIRMATION DRIVING PATTERN

NOTICE:

When performing the normal judgment procedure, make sure that the driver door is closed and is not opened at any time during the procedure.

HINT:

After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

Connect the GTS to the DLC3.
Turn the ignition switch to ON and turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the ignition switch off.
Turn the ignition switch to ON (READY) and turn the GTS on.
Wait for 3 seconds or more. [*]
HINT:

[*]: Normal judgment procedure.

The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
Enter the following menus: Chassis / Brake/EPB / Utility / All Readiness.
Check the DTC judgment result.
HINT:
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE, perform driving pattern again.

WIRING DIAGRAM

Refer to DTC C120200.

Click here

CAUTION / NOTICE / HINT

NOTICE:

After replacing the No. 1 skid control ECU (brake booster with master cylinder assembly), perform "Calibration" after performing "Reset Memory".

Click here

PROCEDURE

1.	CHECK BRAKE FLUID LEVEL

(a) Check that the brake fluid level is sufficient.

HINT:

If the fluid level is low, check for fluid leaks, and repair as necessary.

(1) Check for brake fluid leaks (connection between the brake booster with accumulator pump assembly, brake actuator assembly, brake booster with master cylinder assembly and wheel cylinders).

HINT:

If no leaks exist, add and adjust fluid using the GTS.

Click here

(b) Check that there are no leaks from the connections between the brake booster with accumulator pump assembly, brake actuator assembly and brake booster with master cylinder assembly.

HINT:

As a visual check is very difficult, perform the check with the following procedure.

(1) Bleed the air from the brake system.

Click here

(2) Turn the ignition switch off.

(3) Disconnect the A103 brake pedal stroke sensor assembly connector.

(4) Depress the brake pedal several times to operate the pump motor, then wait until it stops.

(5) After the pump motor stops, wait for 30 seconds, then check the drop in the accumulator pressure sensor output value and the state of the pump motor.

Chassis > Brake Booster > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

ECB Motor Relay

Motor relay operation request

OFF / ON

OFF: Relay off

ON: Relay on

ECB: Electronically Controlled Brake System

Accumulator Pressure

Accumulator pressure output value

Min.: 0.00 MPa

Max.: 24.48 MPa

15.00 to 21.00 MPa (Pressure stable and pump motor stopped)

When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator

Chassis > Brake Booster > Data List

Tester Display
ECB Motor Relay
Accumulator Pressure

Result	Proceed to
The drop in the accumulator pressure sensor output value is less than 2.50 MPa 30 seconds after the pump motor stops, and the pump motor does not operate within 30 seconds after the pump motor stops.	A
The drop in the accumulator pressure sensor output value is 2.50 MPa or more 30 seconds after the pump motor stops, or the pump motor operates within 30 seconds after the pump motor stops.	B

CHECK AND REPAIR BRAKE FLUID LEAKS OR ADD FLUID

2.	INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

(a) Turn the ignition switch off.

*a	Component without harness connected (Brake Fluid Level Warning Switch (Brake Booster with Master Cylinder Assembly))

(b) Reconnect the A103 brake pedal stroke sensor assembly connector.

(d) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

(e) Disconnect the A107 brake fluid level warning switch (brake booster with master cylinder assembly) connector.

(f) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(g) Measure the resistance according to the value(s) in the table below.

HINT:

A float is located inside the brake booster with master cylinder assembly. Its position changes according to the level of brake fluid.

Standard Resistance:

Tester Connection

Condition

Specified Condition

1 (+) - 2 (E)

Brake fluid level warning switch (brake booster with master cylinder assembly) off (float up)

1.84 to 2.16 kΩ

1 (+) - 2 (E)

Brake fluid level warning switch (brake booster with master cylinder assembly) on (float down)

Below 1 Ω

(Brake fluid level is low)

(h) If there are no problems after completing the preceding inspection, adjust the brake fluid to the MAX level with the ignition switch turned to ON.

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

3.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - BRAKE FLUID LEVEL WARNING SWITCH)

(a) Turn the ignition switch off.

(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A104-12 (LBL) - A107-1 (+)	Always	Below 1 Ω
A104-12 (LBL) or A107-1 (+) - Body ground	Always	10 kΩ or higher
A107-2 (E) - Body ground	1 minute or more after disconnecting the cable from the negative (-) auxiliary battery terminal	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK BRAKE DISC

(a) Reconnect the A104 No. 1 skid control ECU (brake booster with master cylinder assembly) connector.

(b) Reconnect the A107 brake fluid level warning switch (brake booster with master cylinder assembly) connector.

(d) Perform a road test according to Freeze Frame Data or customer problem analysis. While driving, check for abnormal brake pedal vibration caused by brake discs that are worn or have excess runout.

OK:

Brake pedal does not vibrate during braking.

HINT:

An unevenly worn disc may vibrate the caliper pistons and cause fluctuations in brake line pressure, triggering a malfunction detection condition.
The brake pedal does not kick back due to caliper piston vibration during electronically controlled brake system control.
If the brake pedal stroke sensor assembly connector is disconnected, the fail-safe function will prohibit electronically controlled brake system control.
The Active Test does not prohibit electronically controlled brake system control when the vehicle is being driven, so disconnect the brake pedal stroke sensor assembly connector before continuing with inspection.
Uneven disc wear can be checked by measuring the disc thickness variation.
for Front Brake: Click here

for Rear Brake: Click here

REPLACE BRAKE DISC

CLEAR DTC

(a) Turn the ignition switch off.

(b) Reconnect the A103 brake pedal stroke sensor assembly connector.

Chassis > Brake Booster > Clear DTCs

(d) Turn the ignition switch off.

6.	RECONFIRM DTC

(a) Based on the Freeze Frame Data and interview with the customer, attempt to reproduce the conditions when the malfunction occurred.

(b) Check if the same DTC is output.

Chassis > Brake Booster > Trouble Codes

Result	Proceed to
DTC C126E15 is not output.	A
DTC C126E15 is output.	B

USE SIMULATION METHOD TO CHECK

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY